1. Field of the Invention
The invention relates to the field of computer controlled and laser guided portable machines for machining parts or work-pieces and, in particular, to a machine that uses a laser position determination system to correct errors in the position of the machining head due to uncontrolled movements of the machine or work-piece.
2. Description of Related Art
Computer controlled milling machines and the like are old in art. They generally consist of a very rigid rails to which is mounted a movable carriage containing a head for mounting a cutter or other tool. The work-piece to be machined is mounted on a very rigid platform and the head is moved thereover. Such machines are so rigid that the head and tool can be precisely positioned under the control of a computer.
Some machines, by the nature of their design, can not position the head and tool to a precise position and thus require supplemental alignment systems. For example, U.S. Pat. No. 5,302,833 “Rotational Orientation Sensor For Laser Alignment Control System” by M. R. Mamar, et al.
U.S. Pat. No. 5,044,844 “Machining Apparatus” by A. E. Backhouse discloses a machine wherein the machining head is mounted on a carriage located on the end of a boom. The boom pivots in a horizontal plane about an axis on spaced circular rails. A laser alignment system senses any inaccuracies in the level of the rails and adjusts the machining head accordingly. However, this system assumes that the cutting head is always properly positioned. This is because the boom and carriage are robust assemblies and only subject to rail inaccuracies. A somewhat similar system is disclosed in U.S. Pat. No. 5,240,359 “Machining Apparatus” also by A. E. Backhouse.
U.S. Pat. No. 5,768,137 “Laser Aligned Robotic Machining System For Use In Rebuilding Heavy Machinery” by R. J. Polidoro, et al. discloses a positioning system for resurfacing and repairing rails and guideways of large heavy machinery. A monorail assembly incorporating the milling head is assembled parallel to the rail. The straightness of the rail is determined by a laser measurement system. This information is fed to a computer and is used to align the monorail with the rail. The rail can then be machined to bring it back into tolerance. However, this machine requires a complex set up procedure and is only adapted to machine rails. It could not be used to machine molds and the like.
None of the above machines are capable of being brought to a remote site and used to machine a work-piece that has been previously setup in a fixed position. All of the prior art machines require precise alignment of the work-piece to the machine. In addition, none of the prior art machines automatically monitor the position of the cutting head and insure that it is in the proper position during machining operations; thus compensating for any movement of the machine or work-piece.
Thus, it is a primary object of the invention to provide a portable machine for performing machining operations.
It is another primary object of the invention to provide a portable machine for performing machining operations on a work-piece that does not require precise positioning of the machine prior to commencement of machining operations.
It is a further object of the invention to provide a portable machine for performing machining operations on a work-piece that automatically compensates for any movement, inadvertent or otherwise, of the machine or work-piece being machined.